Overall Component This project supports continued funding for the National Xenopus Resource (NXR) located at the Marine Biological Laboratory in Woods Hole, MA and identified as one of two top priorities for the Xenopus community. The NXR was established in 2010 to serve as a national resource for researchers working with the Xenopus amphibian model system, which includes two species Xenopus laevis and Xenopus tropicalis. The NXR serves as a national repository for community-generated animal stocks as well as serving as an advanced training venue that greatly facilitates productivity for a multitude of researchers. It is a community-oriented resource center that serves all Xenopus researchers, including individuals from large research-focused universities to small liberal arts colleges. As biological research becomes ever more complex, often requiring specialized animal lines and involving diverse technologies, individual laboratory units become insufficient to meet all of the demands required for addressing significant biological problems and a centralized repository or stock center becomes essential. There are five main aims to this grant. First, the NXR will maintain current stocks of frogs as well as obtain new lines making them available to the community; this includes special inbred, wild type and mutant lines of both species. In the second aim we outline the NXR custom research services for creating transgenic and mutant animals that are offered to the research community. In the third aim we outline the resources that we have created for the Xenopus community that helps to facilitate the use of new techniques in the community. These resources benefit from the excellent MBL facilities for research, teaching and housing. This includes the development of new advanced training workshops taught by experts in each field that serve to teach and propagate specialized techniques; this includes workshops on bioinformatics, imaging, genome editing, transgenesis and husbandry. In this aim we also outline the research hotel service, which provides opportunities for researchers to come to the MBL for short-term visits and use NXR resources. The last two aims are focused on applied research. In Aim 4 we describe new transgenic technology and enhancement of the new genome editing technology. In the last aim we propose to optimize sperm cryopreservation in X. laevis and develop a new health screening PCR service to test for the presence of specific pathogens.